Preventative IMS bearing replacement for 996 and 997.1 Porsche 911. The most important engine protection job on M96 and early M97 engines. Marleston SA.
The IMS (intermediate shaft) bearing is a sealed ball bearing that supports the intermediate shaft in the M96 engine fitted to the 1998–2005 Porsche 911 (996) and the early M97 engine in the 2005–2008 997.1. The bearing is lubricated by a sealed grease pack rather than engine oil — which means it cannot be serviced and will eventually run dry and fail.
When the IMS bearing fails, it typically does so catastrophically and without warning. The bearing collapses, the intermediate shaft loses support, and the resulting debris causes immediate and catastrophic engine damage. Repair costs start at $15,000 and can exceed $25,000 for a complete engine rebuild or replacement on a 997.
IMS bearing failure is not certain on every M96 engine — many have reached 200,000km without issue. But the failure rate is high enough that Rennen recommends preventative IMS bearing replacement on all 996 and 997.1 models where the original bearing has not been replaced.
IMS bearing replacement requires removal of the gearbox to access the rear of the engine. Since gearbox removal is the majority of the labour cost, Rennen strongly recommends combining the IMS bearing replacement with a rear main seal (RMS) replacement and an AOS (air-oil separator) service at the same time — the access is already gained and the marginal cost of doing all three together is significantly lower than doing them separately.
The replacement bearing is the LN Engineering IMS Solution — the definitive aftermarket fix that replaces the sealed ball bearing with an oil-fed unit lubricated by engine oil pressure. Once fitted, the IMS failure risk is effectively eliminated.
Rennen has carried out many IMS bearing replacements on Adelaide 996 and 997 owners' cars. Call 0412 888 441 to discuss your specific 911's history and whether IMS replacement is recommended.
996 Carrera / Carrera S / Carrera 4 (1998–2005): M96 engine. IMS replacement strongly recommended on all examples where the original bearing remains.
997.1 Carrera / Carrera S (2005–2008): early M97 engine shares the IMS design. Replacement recommended.
996 GT3 / GT3 RS: uses a different engine (GT3 spec) that does not have the IMS issue. No replacement required.
997.2 (2009–2012): updated engine design — no IMS bearing in the traditional sense. No replacement required.
986 / 987 Boxster: shares the M96/M97 engine and the IMS issue. Same recommendation applies.
Because IMS bearing replacement requires gearbox removal, the most cost-effective approach is to address all rear-of-engine items at the same time. Rennen recommends the following package for any 996 or 997.1 with unknown IMS history:
Call 0412 888 441 for a specific quote on your 911 model year and current mileage.
Yes, Rennen recommends preventative IMS bearing replacement on all 996 and 997.1 models where the original bearing has not been replaced. IMS failure causes catastrophic engine damage costing $15,000+.
IMS bearing replacement requires gearbox removal. Rennen recommends combining it with rear main seal (RMS) replacement and AOS service at the same time since access is already gained.
Contact Rennen on 0412 888 441 for a specific quote. The cost depends on the model year and whether the IMS + RMS + AOS package is required.
The M96 engine (996 Carrera 1998-2005) and early M97 engine (997.1 Carrera 2005-2008) have IMS bearing vulnerability. The 997.2 (2009+) and 991/992 do not have this issue. The 986/987 Boxster also has IMS concerns.
Porsche specialist in Marleston, Adelaide. PPN member. PIWIS diagnostics. Call 0412 888 441.